I'm planning an Exchange server installation within the next few weeks. We don't have an DMZ or FE/BE for Exchange and I'm concerned about allowing SSL and SMTP traffic straight into our LAN. We have a PIX as our perimeter firewall here lies my question: Is a PIX (SMTP, SSL open) alone secure enough or should I put ISA somewhere in the mix? I've read some articles suggestoing SSL through PIX is a vulnerability as PIX cannot read encrypted traffic. Anyone have any comments on this?